Over the years, a number of various types of windshields have been developed for the convenience, comfort and safety of motorcycle riders. The windshields are either mounted directly on the motorcycle handlebars or form the top portion of a more complex fairing assembly, such as the one shown in U.S. Design Pat. No. 245,904 (to Fetter). The windshields are all designed to deflect the airstream from the rider and even the passenger's face as the motorcycle is ridden.
Because motorcycles are ridden in a variety of weather conditions, it is not always desirable to deflect all of the air around the driver. Particularly in very hot weather, it is desirable and necessary to adjust the amount of ventilating air which reaches him and his passenger. Accordingly, various vent wings have been developed and sold. To date, all of the vent wings are "add-on" devices which clamp to the edge of an existing wind screen and which utilize hinges oriented basically in a horizontal plane and engage the edge of the vent or wind screen which is aligned with the edge of the windshield to which it is to be hinged. U.S. Pat. No. 4,089,556 shows hinged side vent wings which are movable relative to the main windshield to allow the handlebars to be moved without interference with the handlebars.
The addition of add-on vents to existing windshields has not always been successful. The prior art mechanical hinges are susceptible to wear and often exhibit a marked loosening as they are used. This results in loose vents which can be unsatisfactory because they do not remain in the position in which the driver adjusts them. Also, because the vents are hinged along an edge rather than on the top and bottom of the vent, they are typically added only to the outside edge of an existing windshield and, therefore, may not provide a sufficient adjustment of the air flow reaching the driver without radically altering the flow pattern of the air across the windshield and inducing severe turbulent flow to deflect at least some air to the face of a driver positioned in the shelter of a windshield which partially wraps around his face.